Quote from Sam J.
You need 'serious' legal advice, and 'serious' thought before you continue your plan of becoming licensed as a nurse with assault charges, regardless of their outcomes. This forum is chock full of people with far less serious offenses that, if they did get into school and graduate, were denied a license by their BON. A lawyer is a lot less expensive than a possibly futile nursing diploma/degree.
I couldn't agree more. You're going to need to seek some really
serious advice from a knowledgeable lawyer. The reason is that while you were able to get those charges dismissed, the conviction still did occur and it's likely that your local BRN would be able to "see" the charges, conviction, dismissal, and the like even if the conviction was legally expunged. The worst part of all is that the BRNs typically won't be able to really evaluate things until after you've completed your training and have formally submitted your application to them.
Get a good lawyer... you'll need it!